Back to EveryPatent.com
United States Patent | 6,041,031 |
Ichimura ,   et al. | March 21, 2000 |
An optical disc recording/reproduction apparatus for recording and/or reproducing a data by applying a beam from an optical head unit through a substrate onto/from a recording layer of the optical disc through, wherein the substrate of the optical disc is 0.3 mm or below; the optical head unit comprises: an objective lens for converging an incident beam and emitting the beam toward the optical disc; a forward lens for converging the beam introduced through the objective lens and applying the beam to the optical disc; a lens holder where the objective lens and the forward lens are fixed; and an actuator for driving the objective lens and the forward lens as a unitary block and controlling at least focusing, the objective lens and the forward lens having a total numerical aperture of 0.8 or above.
Inventors: | Ichimura; Isao (Kanagawa, JP); Maeda; Fumisada (Tokyo, JP); Yamamoto; Kenji (Tokyo, JP); Ohsato; Kiyoshi (Chiba, JP); Watanabe; Toshio (Kanagawa, JP); Suzuki; Akira (Kanagawa, JP) |
Assignee: | Sony Corporation (JP) |
Appl. No.: | 994455 |
Filed: | December 19, 1997 |
Dec 20, 1996[JP] | P08-340904 |
Current U.S. Class: | 369/13.32; 369/44.14; 369/44.23; 369/112.24 |
Intern'l Class: | G11B 007/00 |
Field of Search: | 369/44.23,44.14,44.12,112,119 |
5764613 | Jun., 1998 | Yamamoto et al. | 369/44. |
5881042 | Mar., 1999 | Knight | 369/44. |
5946282 | Aug., 1999 | Hirono et al. | 369/44. |